SDC2 and arthritic joint disease: SDC2 (Syndecan-2), a transmembrane proteoglycan, regulates matrix metalloproteinases [27] whose dysregulation is a hallmark of OA [28], participates in cellular signaling pathways related to arthritis [29], has osteoblastic functions that affect bone remodeling [30] and is overexpressed in synovial membrane of OA patients [31].